VAUXHALL ASTRA WIRING PROBLEM

2008 Vauxhall Astra • 68,000 miles

Hi I just changed cylinder head and all gaskets on 08 1.4 astra after pluging back in wiring cant get no response from starter when I try to start have checked immobiliser and reprogramend back s/code and key but still the same have had it on diagnostic machine seems to be pointing to under bonnet electrics any one give me an idea as to what I may have missed thanks